Hot pressure welded honeycomb passageway panels and like structures



Sept. 12, 1961 B. L. BAXTER 2,999,306

HOT PRESSURE WELDED HGNEYCOMB PASSAGEWAY PANELS AND LIKE STRUCTURES 2 Sheets-Sheet 1 Filed Nov. 19, 1956 STAC K 1'} INTEGRAL PANEL 4;

a 4 N m T C E S FIG. 4

Hill Hllll HONEYCOMB I21 INVENTOR.

BRUCE L. BAXTER ATTORNEY Sept. 12, 1961 BAXTER Filed Nov. 19, 1956 STACK 14w IST.

B. HOT PRESSURE WELDED HONEYCOMB PASSAGEWAY PANELS AND LIKE STRUCTURES 2 Sheets-Sheet 2 IN V EN TOR.

BRUCE L. BAXTER ATTORNEY 2,999,306 HOT PRESSURE WELDED HONEYCOMB PASSAGE- WAY PANELS AND LHE STRUCTURES Bruce L. Baxter, Louisville, Ky., assignor to Reynolds Metals Company, Richmond Va., a corporation of Delaware Filed Nov. 19, 1956, Ser. No. 622,901 Claims. (Cl. 29--157.3)

This invention relates to the manufacture of metal honeycomb structures.

One previous method of making a honeycomb panel from a plurality of corrugated metal strips comprises: positioning one strip alongside another with their convex bends in abutting relationship; then individually welding the abutting bends together; and repeating these steps sited States Patent'G F for each additional strip. This method, like other prior panels using aluminum sheets; to provide a simple meth-,

0d of manufacturing honeycomb heat exchanger panels from metal sheets; .and to provide a honeycomb heat exchanger panel having internal liquid passages extending transversely of the honeycomb passages.

The objects of my invention are achieved by: assembling a stack of superposed metal sheets with appropriate patterns of spaced parallel stop-weld strips sandwiched between them, the alternate patterns being aligned with each other and transversely offset from the intermediate patterns which are aligned with each other; welding the bare contacting surfaces of the stacked sheets together outside of the stop-weld areas by applying heat and pressure to the stack as a whole; and separating adjacent sheets along the non-welded areas to form a plurality of honeycomb passages.

If the panel is designed to include liquid passageways, v

the stack is assembled with appropriate passageway patterns of stop-weld material interposed between selected sheets, and, after the bonding operation, liquid passageways corresponding thereto are formed by hydraulic expansion preferably after the honeycomb passageways have been formed. These liquid passageways preferably are made to extend'transversely to the honeycomb passages; hence they follow a tortuous path as they cross the surfaces of successive rows of honeycomb passages.

The invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a fragmentary view, in exploded perspective, of a stack of honeycomb panel sheets prior to being welded;

FIG. 2 is a schematic elevational view of a stack of sheets being pressure welded;

FIG. 3 is a perspective view of an integral welded panel, which has been transversely cut to provide a panel section;

FIG. 4 is a schematic elevational view of a panel section in the process of being expanded to form a honeycomb;

FIG. 5 is a fragmentary view of one face panded honeycomb;

FIG. 6 is a fragmentary view, in exploded perspective, I of a stack of heat exchanger honeycomb panel sheets V prior to being welded;

FIG. 7 is a perspective view of an integral welded panel panel, which has been transversely cut to provide a section;

FIG. 8 is a fragmentary view of one face of a heat cxfl changer honeycomb after the honeycomb passages have been expanded but before the expansion of the liquid passageways;

FIG. 9 is a schematic perspective of a honeycomb heat exchanger connected to the apparatus for expandin its liquid passageways; and

FIG. 10 is a section taken on lines 10-40 of FIG. 9.

FIGS. 1-5

In accordance with the invention, the stack-forming as- ,sembly 1 of FIG. 1 is composed of a plurality of superposed metal sheets 2 with an appropriate pattern of stopweld strips 3 sandwiched between successive sheets. The stop-weld strips may be composed of any suitable material, such as those conventionally employed in the art of making pressure welded passageway panels. Each pattern comprises a plurality of spaced, parallel stop-weld strips 3. The width of the spacing between strips preferably is less than the width of the strips 3 but this isn't essential. The strips of the alternate patterns '3 are aligned with each other and offset transversely from the The assembled sheets 2 of the stack 1 are then welded together outside of the stop-weld areas by applying a suitable amount of heat and pressure. This operation,

which bonds the stack into an integral panel 4, may be performed in any suitable apparatus such as that schematically indicated in FIG. 2, which comprises a fixed heated die 6 and a movable heated ram 7.

The panel 4 (FIG. 3) is then severed along lines ex-. tending transversely across the stop-weld strips 3 to provide integral sections 4a having a vertical dimension or thickness equal to the thickness of the panel, a length equal to-the length or width of the panel and a depth dimensioned to correspond with the thickness desired in the finished-honeycomb.

A section 4a is next clamped between the opposing jaws of a vise 9 '(FIG. 4) and its unwelded portions, which enclose the stop-weld strips 3 are progressively expanded or separated into honeycomb passages 10 by suitable means such as the tool 11 shown in FIG. 4. The I tool 11 comprises: a moving endless belt mounted between spaced pulleys; and a succession of spaced rows of teeth mounted on-the belt, the teeth of each row corresponding in number and relative position to the number and relative positions of the completed honeycomb passages 10 in each row. As the belt of the tool 11 moves around the left hand pulley, upward and to the right, 7,

the teeth progressively enter corresponding unwelded areas 10 and expand or pull the section 4a into a completed honeycomb 12 having individual honeycomb passages 10 as seen in FIG. 5.

Patented Sept. 12, 1.961

of an ex- A modified method is illustrated in FIGS. 6 to for making a honeycomb transversely arranged liquid passageway for heat transfer purposes. Here again the stack-forming assembly 14 (FIG. 6) is composed of a plurality of metal (preferably aluminum sheets 2. (nine shown) with an appropriate honeycomb pattern of stopweld strips 3 conventionally sandwiched between desired sheets of the stack. In the arrangement illustrated, the

strips 3 are printed on each top face of the second,

fourth to sixth and eighth and ninth sheets, but omitted from the top face of the third sheet from both top and bottom of he stack.

The honeycomb patterns formed by strips 3 are identical to the patterns of FIG. 1; hence, comprise spaced parallel strips 3 of stop-weld material extending parallel to each other with the strips on the second, fifth and eighth sheets being aligned vertically with each other but ofiset transversely from the strips on the fourth, sixth and ninth sheets, which are vertically aligned with each other.

The top face of the third and seventh sheets 2 of the stack 14 are printed with a stop-weld pattern of liquid passageway strips 15. The strips of each passageway pattern extend parallel to each other and at right angles to the strips 3 of the honeycomb patterns. Preferably each strip 15 of one pattern is vertically aligned with one strip 15 of each other passageway pattern.

The contacting faces of the sheets 2 of stack 14 are pressure welded together throughout their bare surface areas, or, in other words, throughout all surface areas which are not separated by stop-weld material. This may be done in a suitable apparatus such as shown in FIG. 2. Where the liquid passageways ultimately formed along strips 15 must withstand substantial internal pressure, it may be desirable to pressure weld each sheet 2, which contains the liquid passageway pattern of strips 15,

and the adjacent sheet, which covers that pattern, into a composite sheet before assembling the stack 14. This could be done by superposing a pair of foreshortened sheets with an interposed foreshortened pattern of strips" welded potential honeycomb-forming areas 2 corresponding to the strips 2 and a plurality of unwelded potential liquid-passageway-forming areas 15 corresponding to the strips 15.

The panel 16 may now be processed in the same mannor as panel 4. This involves: severingit into a plurality of sections 16;; by vertical cuts extending parallel to and centrally between adjacent liquid passageway areas 15; and then expanding each section by successively opening each row of unbonded honeycomb areas 2 with a suitable apparatus such as shown in FIG. 4, to form the openings 10 which characterize the honeycomb 17 shown in FIGS. 8 and 9.

After the completion of the expansion of the honeycomb passages 10, the potential liquid-passageway-formirrg areas 15 are then connected through conduit 18 to a source of hydraulic pressure 19 and hydraulically expanded by the introduction of liquid under pressure to form a heat exchanger 20 having a pair of liquid pasessence sageways 21. During expansion the opposite end of the potential passages 21 may be plugged or held closed by suitable means.

In the completed honeycomb heat exchanger 20, shown in FIG. 10, the liquid passageways 21 extend in a tortuous path at right angles to and between adjacent honeycomb passages lil which are themselves modified in shape by the hydraulic expansion of the passageways 21. When desired, two or more honeycomb heat exchangers 20 may be joined together along edges, corresponding to the upper and lower edges seen in FIG. 10, to provide a larger heat exchanger of desired size. This type of heat exchanger is particularly suited for use as an automobile radiator.

Having described my invention, I claim:

I l. A method of making a honeycomb panel comprising: assembling a stack of superposed metal sheets together with an appropriate pattern of stop-weld material sandwiched between certain sheets, each pattern being composed of a transverse row of spaced parallel longitudinally extending strips of stop-weld material, the alternate patterns being aligned. with one another and ofiset transversely from the intermediate patterns which are aligned with each other; applying heat and pressure right angles to said row of passages and away from the unexpanded portion of said panel so as to effect the simultaneous expansion of said given row of passages and by successively repeating said insertion and expansion oporation for each succeeding row of passages.

2. The method of claim 1 wherein: the stack is assembled with a liquid'passageway pattern of stop-weld material interposed between certain other sheets to extend transversely across said sheets and said longitudinally extending strips of stop-weld material; and the sheets are bonded outside of said liquid passageway pattern so that said integral panel is formed with an unwelded area corresponding to said liquid passageway pattern.

3. The method of claim 2 including: expanding the unwelded portions corresponding to the liquid passageway after the honeycomb passages are expanded.

4. The method of claim 1 including: the step of cutting the unexpanded integral panel transversely across said potential honeycomb passages into several elongate sections, each section having a length corresponding to the transverse dimension of said unexpanded panel, a thickness corresponding to the thickness of said unexpanded panel and a width corresponding to the thickness desired in the final honeycomb panel formed by that section.

5. A method of making a honeycomb heat exchanger panel comprising: assembling a stack of superposed metal'sheets together with an appropriate pattern of stopweld material sandwiched between certain sheets, each pattern being composed of aplurality of spaced parallel strips of stop-weld material, extending longitudinally 5 passageways between said certain sheets and a trans versely extending potential liquid passageway system between said certain other sheets; mechanically expanding said potential honeycomb passageways; and thereafter hydraulically expanding said potential liquid passageway system by introducing fluid pressure into it.

References Cited in the file of this patent UNITED STATES PATENTS 6 Sendzimir Aug. 20, 1940 Merriman Aug. 26, 1952 Long Dec. 15, 1953 Grenell Sept. 28, 1954 Simmons Apr. 3, 1956 Adams Oct. 16, 1956 Steele Apr. 30, 1957 Otten Aug. 27, 1957 Grenell Aug. 5, 1958 Sims Aug. 11, 1959 

